One year, after 14 straight annual fishing trips, June (Maya Rudolph) and Oscar (Fred Armisen) decide to change up their routine and go skiing. Neither of them has ever skied before. They are middle-aged. It is perhaps too late for all this. They find themselves, freezing and unsteady, tottering on a bunny hill.

“Forever,” whose eight bittersweet, loopily funny episodes arrive Friday on Amazon Prime, goes through a lot of narrative slaloms from there. But you can understand most of its consistent themes from this early scene. At heart, it’s a comedy about love, stasis and change — whether you can transform your life after you’ve decided that your life is all it’s ever going to be, and what happens after you push yourself downhill, or get pushed.

The series sets its tone, and the terms of June and Oscar’s marriage, in a jazz-scored opening montage. Vignettes pass from right to left: they meet, they fall in love, they move in together, they brush their teeth, they go fishing, they go fishing, they go fishing. It’s a picture of a sweet, dull life, and the visual effect is of panning from room to room, unable to move backward and change direction.

The pair have a bantering, best-pals rapport, passing time on a long drive by debating the best way to spend a half-hour. (Sex comes well down the list, after getting a massage and looking at your phone, and they both agree that thirty minutes is “a little long.”) Materially comfortable and unencumbered by children, they have the life rhythms of a prematurely retired couple, though they both work.

The hitch, as the opening suggests, is that June is ready for something different and Oscar is not. Things do change, and this is where I must get vague.

If you’ve heard anything about “Forever,” you’ve probably heard nothing. That is, you’ve heard that it takes some sharp turns and goes places you didn’t expect to follow it to, and that it would be unsporting for a reviewer to say much more.

That’s all true, and thus I’ll zip it about most of what happens beyond the first episode. You will think you have figured out what kind of show “Forever” is, and you will be wrong, and you will figure it out again, and you will be wrong again. (The show is best binged quickly; if it’s not for you, you’ll probably know three episodes in.)

But in another sense, “Forever” is the same story from beginning to end. It’s a narratively nimble show that’s thematically about routine, emotional fidelity and the possibility, or impossibility, of reinvention.

“Forever” was created by Alan Yang and Matt Hubbard, and at times it’s like “Master of None,” the Netflix relationship comedy that Mr. Yang created with Aziz Ansari, but from the other side of commitment. It keeps turning over in its hand the weird idea of monogamy, wondering how people can manage being with one person indefinitely, and how they can manage not being so.

Ms. Rudolph, a comedic typhoon who’s shown dramatic nuance when given the chance (like in the 2009 film “Away We Go”) carries the series’ tone shifts remarkably. You expect her to pull off the big, broad stuff — feuding with a tween-age ski brat, belting a song at a party — but there are terrific silent moments that are simply June seeing her reflection, trying to decide if she’s real.

Mr. Armisen is right about half the time as Oscar, a variation on the neurotic, young-old-man character that he played in half his “Portlandia” roles. Maybe because of that history, and his tendency to push his characters to an unsettling, staring-too-long grotesqueness, his character lacks the gravity he needs in the more serious moments.

If “Forever” were a movie — which it easily could have been — you’d say it has third-act problems. The story seems to spiral away from it in the last couple of episodes, and the ending feels like it’s giving itself credit for resolving issues it hasn’t fully addressed.

But “Forever” dares enough, and pulls off a high enough percentage of what it tries, that I found it worth the trip. It manages to be at the same time slice-of-life and cosmically absurd, reflective and irreverent, fantastical and grounded.

One of the best episodes shifts focus entirely, to a different couple who have a conversation that is not about June and Oscar but neatly describes their dilemma. One of them questions the concept of monogamy: “Things change, people change and then you want something different.” The other counters, “If you’re with someone you love, you’ve got to fight for it.”

A typical romantic comedy would leave no doubt that the second answer is the right one. “Forever” is willing to give both a hearing — and to understand that most people, who can live their lives only forward, will never know if a different answer would have been better for them.

It’s a tricky combination of tones “Forever” is aiming for, simultaneously heartfelt and ambivalent. But if the show sometimes gets out over its skis, I give it credit for being willing to strap them on.